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Re: Google's robots.txt handling
From: Stefan Edwards <saedwards.ecc () gmail com>
Date: Mon, 10 Dec 2012 15:28:53 -0500

On Mon, Dec 10, 2012 at 3:21 PM, James Lay <jlay () slave-tothe-box net> wrote:

On 2012-12-10 12:25, Hurgel Bumpf wrote:
Hi list,


i tried to contact google, but as they didn't answer my email,  i do
forward this to FD.
This "security" feature is not cleary a google vulnerability, but
exposes websites informations that are not really intended to be
public.

(Additionally i have to say that i advocate robots.txt files without
sensitive content and working security mechanisms.)

Here is an example:

An admin has a public webservice running with folders containing
sensitive informations. Enter these folders in his robots.txt and
"protect" them from the indexing process of spiders. As he doesn't
want the /admin/ gui to appear in the search results he also puts his
/admin in the robots text and finaly makes a backup to the folder
/backup.

Nevertheless these folders arent browsable but they might contain
f(a)iles with easy to guess namestructures, non-encrypted
authentications (simple AUTH) , you name it...

Without a robots.txt nobody would know about the existance of these
folders, but as some folders might be linked somewhere, these folders
might appear in search results when not defined in the robots.txt
The
admin finds himself in a catch-22 situation where he seems to prefer
the robots.txt file.

Long story short.

Although google accepts and respects the directives of the robots.txt
file, google INDEXES these files.

This my concern.



http://www.google.com/search?q=inurl:robots.txt+filetype%3Atxt+Disallow%3A+%2Fadmin


http://www.google.com/search?q=inurl:robots.txt+filetype%3Atxt+Disallow%3A+%2Fbackup


http://www.google.com/search?q=inurl:robots.txt+filetype%3Atxt+Disallow%3A+%2Fpassword

As these searches can be used less for targeted attacks, they more
can be used to find victims.



http://www.google.com/search?q=inurl:robots.txt+filetype%3Atxt+%2FDisallow%3A+wp-admin


http://www.google.com/search?q=inurl:robots.txt+filetype%3Atxt+%2FDisallow%3A+typo3
<Just be creative>

This shouldn't be a discussion about bad practice but the google
feature itself.

Indexing a file which is used to prevent indexing.. isn't that just
paradox and hypocrite?

Thanks,


Conan the bavarian


I'm wondering if, in perhaps .htaccess, one could allow ONLY site
crawlers access to the robots.txt file.  Then add robots.txt to
robots.txt...would this mitigate some of the risk?

James


You'd probably end up accidentally block bots though if you did it via ip
range, and you wouldn't be safer at all if you did it by UserAgent string.
I think it'd be safer to just assume robots.txt is going to be looked at by
someone other than actual robots.




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